Various telescopic masts are provided in the prior art where the mast includes a series of tubular sections arranged one inside the next and slidable from a contracted state to an extended state, including the following:
GB2497921 shows an arrangement with a main cable 18 which elevates the second section relative to the main first outer section and then uses a second cable 23 to elevate the third section.
U.S. Pat. No. 3,638,806 shows in FIG. 4 an elevation scheme basically the same as above so that each section is elevated by movement of its next adjacent section by a cable connected between the two.
GB160027 also has two separate cables 10 and 10A with the cable 10A acting to lift the third section as the second section is lifted.